清凉的薄荷精油是如何形成的？

正薄荷是我国传统中药材,也是一种重要的香料植物。薄荷在分类上归属于唇形科薄荷属植物。薄荷属植物还包括椒样薄荷、圆叶薄荷、唇萼薄荷、留兰香等常见植物。薄荷中含有丰富的精油,薄荷精油有特殊的清凉香气,广泛应用于食品和日     

不同类型矮杨梅叶片中槲皮素含量比较

矮杨梅 (ＭｙｒｉｃａｎａｎａＣｈｅｖａｌ.)为杨梅科 (Ｍｙｒｉｃａｃｅａｅ)杨梅属 (ＭｙｒｉｃａＬ .)植物 ,自然分布于我国云南、贵州、西藏和四川的部分地区 ,为我国特有植物 ,具有药用价值和果品开发前景。近年来的研究表明 ,矮杨梅叶中含有黄酮类化合物槲皮素 (ｑｕｅｒｃｅｔｉｎ) ,有祛痰、止咳作用 ,还能对抗自由基 ,在抗癌、防癌、抗菌、消炎及心血管疾病的预防和治疗方面均具有较强的药理活性[1～ 4 ] 。虽然野生矮杨梅分布区范围窄 ,但其种内分化明显。刘宁等[5,6] 的研究表明 ,在矮杨梅根、茎、叶和果实等诸多器官的形态特征…     

3种植物精油对霉菌的抑制作用

肉桂 ( Cinnamomum cassia Presl)别名连桂 ,属樟科樟属 ,常绿乔木 ,高 1 0～ 1 5m,多为栽培 ,主产于广西、广东等地 ,云南、福建等省亦有分布。人们可从其叶、枝或树皮、籽中提取精油 ,精油主要用于医药及食品香精[1 ] 。山苍子 [Litsea cubeba ( Lour.) Pers]别名山鸡椒、木姜子 ,属樟科木姜子属 ,落叶灌木和乔木 ,高 8～ 1 0 m,果期 7～ 8月份 ,我国长江以南各省都有分布。民间广泛使用水蒸汽蒸馏法 ,从其果实中提制精油 ,精油主要用于调配食品、化妆品香精 ,合成其它原料及维生素 [2 ]。丁子香 [Stzygium aromaticum( Linn.)Merr.et…     

元宝草培养物的总黄酮含量

元宝草 (ＨｙｐｅｒｉｃｕｍｓａｍｐｓｏｎｉｉＨａｎｃｅ)为藤黄科金丝桃属植物 ,分布于陕西及江南各地。全草入药 ,用于止血、生肌、调经、抗风湿 ,治疗内出血、肝炎、坐骨神经痛、牙痛和疮肿毒等症效果明显[1,2 ] 。金丝桃属的一些种在国内外民间被广泛作为药用 ,特别是该属所含的金丝桃素具有抗抑郁、抗病毒和治疗脑瘤的辅助作用 ,以及在癌症的光化学治疗及创伤治疗方面的应用 ,引起医药界的极大重视。国内外对贯叶连翘 (Ｈ .ｐｅｒｆｏｒａｔｕｍＬｉｎｎ .)的研究已相当深入[3～ 5] ,人们一直认为金丝桃素为抗抑郁主要活性成分 ,但近…     

基于RAPD标记的薄荷属(Mentha L.)植物亲缘关系分析

应用RAPD标记方法分析了薄荷属(Mentha L. )7个种38个种源间的遗传多样性,并采用UPGMA聚类分析方法探讨了38个种源间的亲缘关系.结果表明,用20条随机引物从38个种源的总DNA中共扩增出111条带,其中多态性条带91条,多态性条带百分率达81.98%,表明薄荷属植物种间和种内存在丰富的遗传多样性.聚类分析结果表明,在遗传相似系数0.43 处,供试的38个种源被分为2大类,其中第1大类包含日本薄荷(M. arvensis L. )、灰薄荷(M. vagans Boriss. )、留兰香(M. spicata L. )、皱叶留兰香(M. crispata Schrad. ex Willd. )、椒样薄荷(M.×piperita L. )和薄荷(M. haplocalyx Briq. )的37个种源,第2大类仅包含唇萼薄荷(M. pulegium L. )1个种源.在遗传相似系数0.74处,38个种源被分为6组:A组仅包含日本薄荷1个种源;B组包含灰薄荷的4个种源;C组包含留兰香的2个种源和皱叶留兰香的6个种源;D组包含椒样薄荷的5个种源和留兰香的2个种源;E组包含薄荷的17个种源;F组仅包含唇萼薄荷1个种源.在遗传相似系数0.83处,B组、C组、D组和E组可各自进一步划分为不同的亚组.研究结果显示,基于RAPD标记分析的聚类分析结果与传统形态学分类结果基本相吻合;同一种类来源相同或相近的种源聚在一起,说明薄荷属植物种内的遗传关系与地理分布和环境差异有一定的相关性.     

薜荔叶及花序托中总黄酮的提取工艺

薜荔 (ＦｉｃｕｓｐｕｍｉｌａＬ .)为桑科 (Ｍｏｒａｃｅａｅ)榕属 (ＦｉｃｕｓＬ .)植物 ,广布我国长江以南各省区。《本草纲目》记载木莲即薜荔 ,有壮阳固精 ,消肿散毒 ,止血 ,下乳 ,治久痢肠痔等功效[1] 。中国科学院药物研究所在抗肿瘤药物的筛选中曾发现薜荔有一定效果[1] 。作者在对薜荔进行成分预试验中发现 ,其叶和花序托的黄酮类物质的含量颇高 ,而黄酮类化合物是一类生理活性较强的化合物 ,近年来在医疗、保健及食品上的应用越来越广泛。为了充分开发利用薜荔 ,扩大黄酮的提取资源 ,对薜荔叶和花序托的总黄酮提取工艺进行了研究 …     

中国大萼苔科一新记录属

钝叶苔属(Ｃｌａｄｏｐｏｄｉｅｌｌａ)隶属于苔类植物的大萼苔科(Ｃｅｐｈａｌｏｚｉａｃｅａｅ),本属有2种:Ｃ.ｆｌｕｉｔａｎｓ(Ｎｅｅｓ)Ｓｐｒ.和Ｃ.ｆｒａｎｃｉｓｃｉ(Ｈｏｏｋ.)Ｂｕｃｈ.,广泛分布于欧洲和北美洲,其中前者在日本有记录。本属我国首次记录,仅发现1种:Ｃ.ｆｒａｎｃｉｓｃｉ(Ｈｏｏｋ.)Ｂｕｃｈ.,分布西藏。钝叶苔属ＣｌａｄｏｐｏｄｉｅｌｌａＢｕｃｈ.,Ｍｅｍ.Ｓｏｃ.Ｆ.Ｆｌ.Ｆｅｎｎｉｃａ5:87,1927.Ｔｙｐｅ:Ｃｌａｄｏｐｏｄｉｅｌｌａｆｌｕｉｔａｎｓ(Ｎｅｅｓ)Ｓｐｒ.植物体纤细,淡绿色。茎具腹面分枝,横切…     

构树属植物的分布及其生物学特性

构树属隶属于桑科Ｍｏｒａｃｅａｅ桑亚科Ｍｏｒｏｉｄｅａｅ构树族Ｂｒｏｕｓｓｏｎｅｔｉｅａｅ ,本属全世界共有 5种 ,分布于亚洲东部及太平洋岛屿 ;我国有 3种 ,即构树、小构树、藤构 (构树组 ) [1] 。主要分布于黄河流域以南地区。构树属各种植物具有广泛的经济及药用用途。其中构树的成熟果实作中药楮实子入药 ,为常见的传统中药 ,历版中国药典均有收载 ,具有补肾清肝 ,明目利尿的功效 ,用于腰膝酸软 ,虚劳骨蒸 ,头晕目昏 ,目生翳膜 ,水肿胀满[2 ] 。本文通过文献调查及实地标本采集 ,对构树属植物的资源分布及生物学特性进行研究 ,为…     

胡桃科6个树种花粉形态的扫描电镜观察

中国有胡桃科( Juglandaceae)植物约7属27种1变种,南方和北方均有分布[1];该科植物通常为落叶或半常绿乔木或小乔木,大部分种类具有药用、材用和食用等价值,其中,青钱柳﹝Cyclocarya paliurus ( Batal.) Iljinsk.﹞为重要的药用植物,其叶的多糖复合物可增强糖尿病小鼠对葡萄糖的耐受力[2-3];胡桃( Juglans regia Linn.)和美国山核桃﹝Carya illinoinensis ( Wangenh.) K. Koch﹞为重要的干果和油料作物,前者也是重要的硬木产品,果皮可用于制造活性炭[4];枫杨( Pterocarya stenoptera C. DC.)是优良的家具用材,其树皮富含纤维[5]。随胡桃科应用价值的不断挖掘,人们对胡桃科植物潜在资源的研究也不断深入。     

牛蒡籽油中脂肪酸成分的气相色谱-质谱联用分析

牛蒡 (ＡｒｃｔｉｕｍｌａｐｐａＬ .)是菊科 (Ｃｏｍｐｏｓｉｔａｅ)牛蒡属(ＡｒｃｔｉｕｍＬ .)植物 ,二年生草本 ,普遍分布于全国各地 ,野生或栽培。其根、叶、瘦果和籽均入药 ;茎皮纤维可造纸 ;根部含大量菊糖 ,可酿酒及作蔬菜食用 ;另外 ,还可以作为蜜源和饲料[1～ 4 ] 。据记载 ,其种子含油 2 5 %～ 30 % ;另据文献报道 ,其脂肪酸的主要成分为软脂酸、硬脂酸及油酸的甘油酯[2 ] 。牛蒡是耐盐植物 ,前人虽对其进行了较多的研究 ,但未见其籽油脂肪酸组成的准确报道 ,本文用气相色谱 质谱联用进行分析 ,以期为耐盐植物的开发利用积累部分…     

我国麦蚜抗药性及研究现状

麦蚜是危害我国小麦Triticum aestivum L.生产的主要害虫,具有分布广、数量大、繁殖力强以及远距离迁飞等特点,不仅直接吸食小麦汁液,还传播多种植物病毒,每年造成小麦减产10%~30%。目前对麦蚜的防控主要以化学防治为主,但由于化学杀虫剂长期或不合理的使用,多地麦蚜对常用杀虫剂产生了不同程度的抗性。本文从麦蚜抗药性测定方法、抗性水平及交互抗性、代谢和靶标抗性机制、以及麦蚜抗药性综合治理等方面进行了综述,以期为麦蚜的防治及杀虫剂的持续合理使用提供理论参考和依据。     

Stability analyses for estimating relative durability of quantitative resistance

Summary Experiments in which a series of host cultivars are inoculated in all combinations with a series of pathogen isolates have been used to detect specificity in the host resistance. A theoretical model of polygenic resistance involving both general and specific interactions with pathogen virulence was developed to test the abilities of statistical analyses to discriminate between host genotypes with different levels of general and specific resistance. Estimates of levels of specific resistance could be obtained in regressions of disease severity scores for each host cultivar X pathogen isolate combination vs. the virulence index of each isolate. If the virulence index was based on the mean disease severity induced by the isolate over all host cultivars, the slopes of the regression lines were correlated with the levels of specific resistance in host cultivars. If the virulence index was based on the disease severity induced by the isolate on a host cultivar with a minimum of specific resistance, the mean squares for deviations from the regression were correlated with the levels of specific resistance in host cultivars. A method was developed to consistently choose host cultivars with minimum specific resistance. The two regression analyses gave estimates of specificity in randomly generated, model genotypes of approximately equal accuracy, although the second method appeared to be more accurate when the numbers of loci controlling resistance and virulence were small. The best estimates of numbers of genes for specific resistance were obtained by calculating a rating based on mean disease severity, the mean square for deviation from the regression on the virulence index based on disease severity on the cultivar with minimum specific resistance and the slope of the regression on the virulence index based on the mean disease severity. The best estimates of proportions of resistance genes that were specific were obtained by calculating a rating based on the above deviation mean square and slope alone.Cooperative investigation of the U.S. Department of Agriculture, Agricultural Research Service and the North Carolina Agricultural Research Service. Journal Series Paper No. 8326 of the North Carolina Agricultural Research Service     

PC12 Variants Deficient in Catecholamine Transport

We have isolated PC12 cell variants deficient in transporter-mediated uptake of 3,4-dihydroxyphenylethylamine (dopamine). The variants either were obtained nonselectively, or they were selected by resistance to guanethidine or N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Dopamine uptake into guanethidine-resistant cells occurred with a decreased Vmax; the Km for dopamine and inhibition by guanethidine were normal. MPTP-resistant cells lacked the capacity to take up dopamine. Most of the variants resembled wild-type PC12 in their response to nerve growth factor and the storage and secretion of dopamine. MPTP-resistant cells exhibited several deficiencies in addition to dopamine transport, i.e., no measurable storage of dopamine or acetylcholine and no observable response to nerve growth factor. Wild-type and variant cells were compared with respect to the labeling of cell proteins with [3H]xylamine, which binds covalently to certain proteins apparently only after entering PC12 via the catecholamine transporter. When intact variant cells were used, there was markedly reduced labeling of the proteins by [3H]xylamine. Almost all of these proteins were readily labeled when cell homogenates were exposed to [3H]xylamine. However, MPTP-resistant cells were missing three of these proteins. Northern blot analysis with cDNA clones revealed that the MPTP-resistant cells had markedly reduced levels of several specific mRNA species.     

西花蓟马的抗药性及其治理策略

西花蓟马Frankliniella occidentalis（Pergande）是世界性的园艺作物上的重要害虫,几乎对每种类型的杀虫剂均产生了抗药性,包括有机磷、氨基甲酸酯、拟除虫菊酯类杀虫剂和多杀菌素等。本文对国外西花蓟马的抗药性发展现状和抗性机制进行了总结,并提出了抗性治理策略,即科学合理使用杀虫剂,结合栽培防治、物理防治、生物防治和寄主植物抗性等方式降低杀虫剂对西花蓟马的选择压,从而达到抗性治理的目的。     

甜菜夜蛾的抗性及抗性机理研究进展

甜菜夜蛾Spodoptera exigua(Hübner)是世界性农业害虫,近年来在我国由次要害虫上升为主要害虫。甜菜夜蛾对很多种化学杀虫剂和生物杀虫剂产生了抗性。本文分别阐述了甜菜夜蛾对常用杀虫剂如有机磷类、拟除虫菊酯类、氨基甲酸酯类、生长调节类杀虫剂、Bt杀虫剂等的抗性发展现状,并且对抗药性机理进行了总结,提出了抗性治理措施。     

Selection of a dexamethasone-resistant H-4-IIE-C3 rat hepatoma tissue-culture line

Summary Exposure of H-4-IIE-C3 rat hepatoma cell cultures to the synthetic glucocorticoid, dexamethasone, results in an inhibition of cellular proliferation which is not the result of steroid-induced cytolysis. A significant decrease in both the rat of DNA synthesis and DNA content precedes, a detectable effect on cell number. Continuous culture of H-4-IIE-C3 cells in medium containing 10⁻⁵ m dexamethasone results in the selection of a steroid-resistant cell population that has the growth characteristics of unselected sensitive cultures and shows normal steroid induction of tyrosine transaminase. Selection is a slow process requiring 24 to 36 months to obtain, a phenotypically stable resitant cell line, and can be subdivided into three phases—a sensitive phase, adaptation and resistance. A comparison of the karyotypes of unselected and resistant cultures shows that the selection process enriches for a dexamethasone-resistant subpopulation. This work was supported by Special Grant No. 716 from the California Division of the American Cancer Society, and a grant-in-aid from the San Diego State University Foundation.     

害虫及害螨对阿维菌素抗药性研究进展

阿维菌素(avermectins)是一类新型高效广谱的生物源农药,对多种害虫及害螨具有极好的防效。随着阿维菌素在害虫及害螨防治中的广泛应用,害虫和害螨对其的抗性问题日益受到关注。文章综述国内外的最新研究结果表明:小菜蛾Pluttella xylostella(L.)、二斑叶螨Tetranychus urticate Koch等已对阿维菌素产生抗性,对阿维菌素产生抗性的害虫和螨并不总是表现适合度劣势,且抗性一旦产生敏感性较难以恢复;抗性遗传多数由多基因、不完全隐性控制;抗性机理涉及多种因素。综合分析发现害虫和螨对阿维菌素存在较大的、潜在抗性风险。     

Herbicide resistance—what have we learned from other disciplines?

Herbicide resistance is a growing threat to agriculture and has parallels to resistances to fungicides and insecticides. However, there are many reasons to treat the resistance to herbicides differently. To highlight these similarities and differences, three pests, a weed, an insect, and a disease that have shown the ability to rapidly develop resistance to a variety of products and product classes were used as illustrations. The situation in herbicide resistance is approaching a point already experienced by the other pest control disciplines, and thus, it is worthwhile to revisit their experiences.